snmpv3: replace arch/cc.h to lwip/arch.h in included files

Only "lwip/arch.h" is expected to include "arch/cc.h". This is the same
spirit than "lwip/opt.h" for "lwipopts.h" and "lwip/sys.h" for
"arch/sys_arch.h".

src/apps/snmp/snmpv3_mbedtls.c

@@ -35,7 +35,7 @@
 
 #include "lwip/apps/snmpv3.h"
 #include "snmpv3_priv.h"
-#include "arch/cc.h"
+#include "lwip/arch.h"
 #include "snmp_msg.h"
 #include "lwip/sys.h"
 #include <string.h>